Gisele: Planning Two Secret Weddings Wasn't Easy

So far, so great, new bride Gisele Bündchen says of married life: "I think I'm the happiest person. You know what the secret to being happy is? Being grateful. And I'm very grateful."

Bündchen, 28, who spoke to PEOPLE at a Wednesday gala benefiting the Rainforest Alliance at New York's Museum of Natural History, certainly has a lot to be grateful for – starting with her new husband, New England Patriots quarterback Tom Brady, 31.

She admits pulling off two top-secret weddings – a Feb. 26 ceremony at a Catholic church in Santa Monica, and a second fete at her Costa Rican vacation home on April 4 – was no easy feat. "We tried very hard to keep it private. Oh my God, you have no idea how hard that was," Bündchen said with a laugh.

Yet it was worth it. "Yes," she said, "we had a great time. I think we were very lucky."

Unaware of Scuffle

Nor did they let reports of a scuffle between security guards and photographers disrupt their joy. "We were all there and nobody heard anything!" says Bündchen of the alleged shooting that took place outside her Costa Rican villa. "The next day people were calling, and I'm like, 'I don't know what you're talking about.' I didn't even know it was happening. Later on, I was like, 'What? What happened on my day?' "

With only their closest friends and family present, "we had a great time," says Bündchen, who is now stepmom to Brady's son John with his ex, Bridget Moynahan. "I think family is the base to everything. I have a lot to be grateful for but I think family is definitely number one."

Her Amazon Project

She is certainly close with her own, visiting her hometown of Horizontina, Brazil, as often as possible and working with her father, Valdir, on an environmental project with the Brazilian government.

"I just started my own project in Brazil with my dad to replant trees," she says. The project, Água Limpa, aims to re-plant deforested areas of the Amazon, to prevent chemicals and pesticides from local farms from seeping into the river water.

"We've planted over 200,000 trees so far," says Bündchen, who is also working with the Rainforest Alliance to promote sustainable business practices. "Fresh water is only so much and you can't reproduce it. I'm behind this cause, and I think it's important to get the message out."